Electronic components, such as solar cells, are often inspected for various types of defects using optical inspection systems. For example, inspecting a working surface of a solar cell for discoloration may be used to detect thickness variations of a silicon nitride antireflective coating. Discoloration inspection may involve multiple inspection parameters that need to be individually set up in order to identify certain defects. Some of these defects may be less important and could be generally ignored, while others may be critical and should be carefully screened for. Setting various thresholds of inspection parameters may be used for this purpose.
Discoloration inspection generally has been a manual process in which an operator looks at the solar cell and visually inspects the surface of the cell to judge the quality. Based on the visual quality the operator then can try to manually adjust inspection parameters on a color image in the inspection system. In addition to being subjective, this approach can also be very labor intensive and prone to human mistakes.